Generally Sound clarity and volume. I have heard battery conserving reports, but have not noticed on mine. The Bluetooth seems to connect better on the newer OS. That and the newer OS's have the newer themes. I have Bharti and I love it. But you can add custom themes if you want without adding the newer OS. Just check the Custom theme corner for a plethora of options

Implied? Bharti is a carrier. If anyone here is confused, then it is time to set it straight. Bharti is a wireless carrier in India. Just like Cingular or Verizon Wireless or Rogers. Bharti happened to have posted an updated version of the BlackBerry Handheld Operating system containing the beloved Zen theme before others. If there is any confusion about what Bharti and Zen are, I hope it's clear now.